Originally used as a general term for single-edged sword, as opposed to tsurugi, which are double-edged swords, the term is now used specifically to describe nihontō that are around 70–90 cm long with a curved blade. This is different from Chokutō, which is a straight blade.

The katana was mostly paired with the wakizashi or shōtō, a similarly made but smaller sword, both worn by the members of the warrior class. It could also be worn with the tantō, an even smaller similarly shaped blade. The two weapons together were called the daishō and represented the social power and personal honour of the samurai. Although the name katana is more common it only refers to the longer swords.

Hey I might mention; a shuriken isn't a ninja weapon. They were primarily a bushi weapon and the most common form was not a 'star' but rather a knife called the kogatana which fit in the kozuka on a katana's fittings.
As ninja were only spies, they didn't have or for that matter need weapons.